Transmissions with electronics interface assembly for torque sensor

ABSTRACT

A transmission includes sensors positioned adjacent respective pairs of magnetized bands on a shaft of the transmission for detecting magnetic flux emanating from the bands in response to torque on the shaft. The transmission further includes an electronics interface assembly configured to respectively provide drive signals to the sensors and to receive from the sensors, in response to the drive signals, output signals indicative of the torque on the shaft as detected by the sensors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.13/114,366, filed May 24, 2011, which is hereby incorporated byreference in its entirety.

TECHNICAL FIELD

The present invention relates to automatic transmissions having torquesensors.

BACKGROUND

An automatic transmission of a vehicle includes an input shaft and anoutput shaft. The input shaft receives an input torque at an input speedfrom power derived from a power source such as an engine. Thetransmission converts the input torque at the input speed to an outputtorque at an output speed. The output shaft transmits the output torqueat the output speed to traction wheels of the vehicle to propel thevehicle.

The transmission converts the input torque at the input speed to theoutput torque at the output speed by adjusting a gear ratio (forexample, during an up-shift or down-shift) between the shafts. Thetransmission shifting is accomplished by applying and/or releasingfriction elements (such as clutches, band-brakes, etc.) to change speedand torque relationships by altering planetary gear configurations ofthe transmission. As a result, power flow paths are established anddisestablished from the engine to the wheels.

The friction elements have to be properly controlled to satisfactorilyshift the transmission. To this end, information regarding the operationof the transmission is used to control the friction elements. Forinstance, information indicative of the input torque received by theinput shaft and the speed of the input shaft may be used. Similarly,information indicative of the output torque transmitted by the outputshaft and the speed of the output shaft may be used.

Torque and speed of the input and output shafts may be estimated basedon available information. On the other hand, magnetic sensors mountedwithin the transmission can directly detect the actual torque and speedof the input and output shafts. However, installation and packaging ofsuch sensors within limited spaces of the transmission presentschallenges.

SUMMARY

Embodiments of the present invention are directed to transmissionshaving electronic interface assemblies for magnetic torque and/or speed(i.e., “torque”) sensors configured to sense torque and/or speed ofinput and/or output shafts in the transmissions.

In one embodiment, the present invention provides a transmissionincluding sensors positioned adjacent respective pairs of magnetizedbands on a shaft for detecting magnetic flux emanating from the bands inresponse to torque on the shaft. The transmission further includes anelectronics interface assembly configured to respectively provide drivesignals to the sensors and to receive from the sensors, in response tothe drive signals, output signals indicative of the torque on the shaftas detected by the sensors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of a vehicle powertrain in accordancewith embodiments of the present invention;

FIG. 2 illustrates a cross-sectional view of an exemplary torqueconverter and an exemplary transmission for the powertrain shown in FIG.1;

FIGS. 3A, 3B, and 3C illustrate an example of a magnetic torque sensorfor detecting torque of a shaft;

FIG. 4 illustrates an example of a magnetic speed sensor for detectingrotating speed of a shaft;

FIG. 5 illustrates another example of a magnetic torque sensor fordetecting torque of a shaft and another example of a magnetic speedsensor for detecting rotating speed of a shaft;

FIG. 6A illustrates a cross-sectional view of an automatic transmissionhaving a magnetic torque sensor packaging design in accordance with anembodiment of the present invention;

FIG. 6B illustrates an enlarged view of the front side of the statorsupport, as partially assembled, of the transmission shown in FIG. 6A;

FIG. 6C illustrates an enlarged view of the wiring for the magnetictorque sensor of the transmission shown in FIG. 6A;

FIG. 6D illustrates a cross-sectional view of the area of thetransmission shown in FIG. 6A near one of the sensor housings of thesensor;

FIG. 6E illustrates a side view of the stator support of thetransmission shown in FIG. 6A;

FIG. 6F illustrates another enlarged view of the front side of thestator support, as partially assembled, of the transmission shown inFIG. 6A;

FIG. 6G illustrates a view of the front side of the stator support, asfully assembled, of the transmission shown in FIG. 6A;

FIG. 7 illustrates a block diagram of a transmission shaft with anelectronics interface assembly for a magnetic torque sensor inaccordance with an embodiment of the present invention; and

FIG. 8 illustrates a block diagram of a transmission shaft with anelectronics interface assembly for a magnetic torque sensor inaccordance with another embodiment of the present invention.

DETAILED DESCRIPTION

Detailed embodiments of the present invention are disclosed herein;however, it is to be understood that the disclosed embodiments aremerely exemplary of the invention that may be embodied in various andalternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

Referring now to FIG. 1, a block diagram of a vehicle powertrain 10 inaccordance with embodiments of the present invention is shown.Powertrain 10 includes an engine 12, a torque converter 14, and anautomatic transmission 16. Transmission 16 has an input shaft 18 and anoutput shaft 20. Engine 12 delivers torque to torque converter 14 viacrankshaft 13 of engine 12 which is connected to torque converter 14.Torque converter 14 converts the engine torque into an input torque atan input speed and transmits the input torque at the input speed toinput shaft 18 of transmission 16. Transmission 16 serves to change atransmission ratio and thus changes the input torque at the input speedinto an output torque (for example, increased torque) at an output speed(for example, reduced speed). Transmission 16 transmits the outputtorque at the output speed to output shaft 20. Output shaft 20 isconnected to a vehicle driveline (not shown) such that the output torqueat the output speed may be used to drive wheels of the vehicle.

Powertrain 10 further includes at least one of an input shaft sensor 22and an output shaft sensor 24. Input sensor 22 is associated with inputshaft 18 and is configured to monitor at least one of (input) torque and(input) speed of input shaft 18. Similarly, output sensor 24 isassociated with output shaft 20 and is configured to monitor at leastone of (output) torque and (output) speed of output shaft 20. Input andoutput sensors 22 and 24 provide sensor signals indicative of themonitored information to a power control module (PCM) (not shown) forthe PCM to control operation of transmission 16.

Referring now to FIG. 2, with continual reference to FIG. 1, across-sectional view of an exemplary torque converter 14 and anexemplary transmission 16 for powertrain 10 is shown. As shown in FIG.2, torque converter 14 is encased within a torque converter case 26 andtransmission 16 is encased within a transmission case 28.

Transmission 16 includes a transmission mechanism 30. Transmissionmechanism 30 is configured to change the input torque at the input speedreceived by input shaft 18 into an output torque at an output speedtransmitted by output shaft 20. As illustrated in the right-hand side ofFIG. 2, transmission mechanism 30 uses planetary gear sets.

Torque converter 14 includes a turbine 32, a stator 34, and an impeller36. Impeller 36 is fixedly connected to engine crankshaft 13 such thatimpeller 36 rotates as crankshaft 13 rotates. Stator 34 is fixed ontothe stator shaft (i.e., the stator tube) of a stator support 40 via aone-way clutch 39. Stator support 40 is fixed to transmission case 28.Turbine 32 is mechanically linked via a turbine hub 42 to input shaft18.

Transmission 16, as shown in FIG. 2, does not have either an inputsensor 22 for directly measuring torque and/or speed of input shaft 18or an output sensor 24 for directly measuring torque and/or speed ofoutput shaft 20.

Transmissions in accordance with embodiments of the present inventioninclude an input sensor 22 and/or an output sensor 24 packaged therein.The packaging of an input sensor 22 and/or output sensor 24 within atransmission enables direct measurement of torque and/or speed of inputshaft 18 and/or output shaft 20. Sensors 22 and 24 may be magnetictorque sensors for monitoring torque of input and output shafts 18 and20, respectively. Likewise, sensors 22 and 24 may be magnetic speedsensors for monitoring speed of shafts 18 and 20, respectively. Further,sensors 22 and 24 may be magnetic torque and speed sensors formonitoring torque and speed of shafts 18 and 20, respectively.

Magnetic torque and speed sensor technology operates optimally with afree smooth surface area on a shaft with constant diameter andcontrolled hardness, wherein a part of the shaft is magnetized. Themagnetic sensor technology makes use of magnetic flux sensing elementssuch as fluxgates. The sensing elements are preferably stationary andfixed with respect to the rotating magnetized surface of the shaft.Translation of the shaft in either the axial or radial directionrelative to the sensor housing is preferably minimized. Conventionaltransmission designs, such as shown in FIG. 2, may represent a challengefor packaging of magnetic sensors.

Input and output sensors 22 and 24 may be magneto-elastic sensors asdescribed in U.S. Pat. Nos. 6,145,387; 6,047,605; 6,553,847; and6,490,934. Other magnetic sensors may also be used to enable accuratemeasurements of torque exerted onto a rotating shaft and rotating speedof the shaft without physical contact between a magnetic flux sensingelement of the sensor and the shaft.

Referring now to FIGS. 3A, 3B, and 3C, an example of a magnetic torquesensor for detecting torque of a shaft will be described. This exampleassumes that the shaft is input shaft 18 and that the torque sensor isinput sensor 22. Sensor 22 includes a magnetic flux sensing element(s)(e.g., a fluxgate(s)) within a sensor housing 44. Sensor housing 44 mayinclude other types of sensing elements such as thermo-couples. Shaft 18includes a magnetized region 46. Magnetized region 46 circumferentiallyextends around shaft 18. Magnetized region 46 may be created by coatingmagnetized material as a thin layer on shaft 18 or by magnetizing shaft18. Sensor housing 44 is fixed in position adjacent to the magnetizedregion 46 of shaft 18 to enable the sensing element of sensor 22 tosense the torque induced signal.

At no load (FIG. 3A), magnetic flux 47 is contained near or within theshaft surface. FIG. 3A shows a simplified view of flux direction.Depending on chosen magnetization patterns, magnetic flux may have morecomplex directional patterns. When load is applied (i.e., shaft 18 istwisted), magnetic flux 47 extends from the shaft surface and its axialcomponent, which is proportional to the applied torque, is measured bythe sensing element (FIGS. 3B and 3C). For instance, as shown in FIGS.3B and 3C, magnetic flux 47 is realigned in one direction when the loadis greater than zero and is realigned in the opposite direction when theload is less than zero. Either realignment causes more magnetic flux 47to come out from the shaft surface in proportion to the load level. Asindicated in FIGS. 3B and 3C, the sensing element detects the magneticflux direction and intensity. Variations of this technology include, forexample, dual band and tri-band magnetic torque sensors.

Referring now to FIG. 4, an example of a magnetic speed sensor fordetecting rotating speed of a shaft will be described. Again, thisexample assumes that the shaft is input shaft 18 and that the speedsensor is input sensor 22. Sensor 22 includes sensor housing 44 having amagnetic flux sensing element(s) (e.g., a fluxgate). Shaft 18 includes amagnetized region 48 comprised of magnetic material placed in spotsrepeatedly around the circumference of shaft 18 as shown in FIG. 4.Sensor housing 44 is placed near the shaft surface. The sensing elementof sensor 22 picks up the circumferential component of magnetic flux asshaft 18 rotates. Variations of this technology include, for example,dual band magnetic speed sensors.

Referring now to FIG. 5, with continual reference to FIGS. 3A-3C and 4,another example of a magnetic torque sensor for detecting torque of ashaft and another example of a magnetic speed sensor for detecting speedof a shaft will be described. Again, these examples assume that theshaft is input shaft 18, the torque sensor is a first input sensor 22 a,and the speed sensor is a second input sensor 22 b.

Regarding first input sensor 22 a for detecting torque of shaft 18, asindicated above variations of the technology described with respect toFIGS. 3A-3C include dual and tri-band magnetic torque sensors. Sensor 22a is an example of a dual band torque sensor. To this end, shaft 18includes a pair of magnetized regions 46 a and 46 b whichcircumferentially extend around shaft 18. Sensor 22 a includes a pair ofmagnetic flux sensing elements 49 a and 49 b (e.g., a pair of fluxgates)within a sensor housing (not shown). The sensor housing is fixed inposition adjacent to magnetized regions 46 a and 46 b of shaft 18 toenable sensing elements 49 a and 49 b of sensor 22 to sense therespective torque induced magnetic flux (M_(r)) 47 a and 47 brespectively emanating from magnetized regions 46 a and 46 b when loadis applied (i.e., when shaft 18 is twisted).

Regarding second input sensor 22 b for detecting rotating speed of shaft18, as indicated above variations of the technology described withrespect to FIG. 4 include dual band magnetic speed sensors. Sensor 22 bis an example of a dual band speed sensor. To this end, shaft 18includes a pair of magnetized bands 48 a and 48 b each having magneticmaterial placed in spots repeatedly around the circumference of shaft18. Sensor 22 b includes a magnetic flux sensing element 49 c within asensor housing (not shown). This sensor housing is fixed in positionadjacent to magnetized bands 48 a and 48 b to sense the magnetic flux(M_(r)) emanating from magnetized bands 48 a and 48 b when shaft 18rotates.

For simplicity, a magnetic torque and/or speed sensor is referred toherein as a “magnetic torque sensor” or simply “sensor”. However, asdescribed above, such a magnetic torque sensor or sensor may be amagnetic torque sensor only, a magnetic speed sensor only, or a magnetictorque and speed sensor.

Referring now to FIGS. 6A, 6B, 6C, 6D, 6E, 6F, and 6G, an automatictransmission 60 having a magnetic torque sensor packaging design inaccordance with an embodiment of the present invention will bedescribed. FIG. 6A illustrates a cross-sectional view of transmission60; FIG. 6B illustrates an enlarged view of a front side 41 of statorsupport 40, as partially assembled, of transmission 60; FIG. 6Cillustrates an enlarged view of the wiring for sensor 22 of transmission60; FIG. 6D illustrates a cross-sectional view of the area oftransmission 60 near one of sensor housings 44 of sensor 22; FIG. 6Eillustrates a side view of stator support 40 of transmission 60; FIG. 6Fillustrates another enlarged view of front side 41 of stator support 40,as assembled, of transmission 60; and FIG. 6G illustrates a view offront side 41 of stator support 40, as fully assembled, of transmission60.

A general aspect of the sensor packaging design of transmission 60includes packaging features of sensor 22 on the front side 41 of statorsupport 40 (i.e., on the side of stator support facing toward torqueconverter 14).

Sensor 22 includes two sensor housings 44 each having two pairs ofsensing elements (e.g., two pairs of fluxgates). Sensor housings 44 areplaced in upper and lower windows 63 cut into the stator shaft (i.e.,the stator tube) of stator support 40 adjacent to magnetized regions 46a, 46 b, and 46 c (cf. FIGS. 7 and 8) of input shaft 18. A firstpress-fitted sleeve 61 seals the hydraulic passages of transmission 60and retains sensor housings 44 from the inside surface of the statorshaft. A second press-fitted sleeve 62 retains sensor housings 44 fromthe outside surface of the stator shaft. Each window 63 is ahollowed-out portion of the stator shaft of stator support 40. As such,sensor housing 44 in respective windows 63 are encased within the statorshaft of stator support 40.

Windows 63 are positioned within the stator shaft of stator support 40circumferentially away from hydraulic passages embedded in statorsupport 40.

To compensate for the effect of temperature on performance of sensor 22,it is desired to measure the surface temperature of shaft 18 at themagnetized region. For practical reasons, the temperature in thesurrounding environment of shaft 18 is measured, instead of directlymeasuring the surface temperature of shaft 18. A temperature sensor(e.g., thermistor) (shown in FIGS. 7 and 8) is integrated into thesealed upper window 63 of sensor housing 44 and reads air temperatureinside of upper window 63.

First sleeve 61 includes a backing plate and a bushing material layer.Both layers include magnetically permeable materials such as non-ferrousmaterials so that the sensing elements can sense through first sleeve61. The backing plate and the bushing material layer have similarcoefficients of thermal expansion. The bushing material at the internaldiameter of first sleeve 61 supports shaft 18 on its journal surface.Sensor housings 44 are placed at an appropriate distance from thejournal area of shaft 18 and the corresponding bushing area of firstsleeve 61. This arrangement is to avoid mechanical work on the torquesensing surface and to prevent debris passing across the magneticimprint on the shaft surface and impact the rotational signal uniformityof the signal of sensor 22. The distance between sensor housings 44 andthe journal area of shaft 18 and the corresponding bushing area of firstsleeve 61 also minimizes the effect of local heating/loadingnon-uniformities on the sensor performance.

Second sleeve 62 can be made of magnetic shield material, such as mumetal or permalloy, to protect the sensing elements from externalmagnetic interference and reduce zero offset variation of the sensingelements. As indicated at 64, second sleeve 62 provides a bushing ridingsurface and an O-ring groove. As indicated at 65, second sleeve 62 canbe extended axially for better electromagnetic shielding. Sensor wiringis glued or otherwise affixed inside of grooves in stator support 40 asindicated at 66. Second sleeve 62 covers the wiring at the OD. The endof the wiring extending out of stator support 40 includes a connector 67for connection to the PCM. As such, second sleeve 62 may be used as abushing surface on the outside and provide a continuous surface for aseal with the front side of stator support 40.

In a variation, four sensor windows 63 offset by 90 degrees are cut intothe stator shaft adjacent to magnetized regions 46 of input shaft 18 andfour magnetic torque sensors are respectively positioned within thesefour windows 63. This configuration enables circumferential signalnon-uniformities of the sensors to be more efficiently cancelled outthan a configuration having only two sensors spaced apart by 180 degreesaround the stator shaft.

Further aspects of the sensor packaging design for transmission 60 willbe described. Windows 63 of the stator shaft may be angled to allowpress fit. The assembled location of first sleeve 61 is indicated atreference numeral 72. Stator support 40 includes on its front side acircumferential groove 74 for combining wiring 82 from sensor housings44 together. Circumferential groove 74 connects with an axial grooverunning along the stator tube. Wiring 82 can be in the form of ribbonwires or can be embedded inside of a plastic lead frame with appropriatestiffness, or can be contained within some protective cover. Statorsupport 40 further includes on its front side a radial groove 77connected to circumferential groove 74. Wiring 84 of sensors furtherextends along radial groove 77. A cover plate 75 for covering radialgroove 77 is bolted onto the front side of stator support 40. Coverplate 75 covers wiring 84 at the top of radial groove 77 such thatgrooves 74 and 77 are protected during subsequent assembly into thetransmission housing (the wiring may be in the form of ribbon wires andplaced into a closed groove at the subassembly level, or containedwithin some protective cover). Alternatively, wiring 84 can be embeddedinside of a plastic lead frame that sits inside radial groove 77. Also,wiring 82 inside circumferential groove 74 can be embedded in a plasticlead frame with appropriate stiffness that connects sensor housings 44together forming a single plastic part with circumferential wiring 82,sensor housings 44, and radial wiring 84. During assembly, sensorhousings 44 snap into their windows 63 on stator support 40, and wirings82 and 84 snap into their respective grooves 74 and 77. Wiring 84extends out of stator support 40 from radial groove 77 as indicated atreference numeral 76.

As shown in FIGS. 6C and 6F, a retainer clip 83 connects wiring segments82 and 84 to sensor housings 44. As shown in FIG. 6D, sensor housing 44and its window has a small angle taper to facilitate snap-in of parts asindicated at 85.

Features of the sensor packaging design described with reference toFIGS. 6A-6G include one or more sensors 22 encased within the statorshaft (i.e., the stator tube) of stator support 40. Accordingly, thissensor packaging design represents a design in which the stator shaft ofthe stator support of an existing transmission may be retrofitted toinclude the hollowed-out containers 63 for sensors 22. Thus, the statorshaft of the stator support of an existing transmission does not have tobe cylindrically recessed or the like to accommodate one or more sensors22.

Referring now to FIG. 7, a block diagram of a transmission shaft with anelectronics interface assembly 90 for a magnetic torque sensor inaccordance with an embodiment of the present invention is shown. Thetransmission shaft is the shaft of a transmission such as transmission60 described above with reference to FIGS. 6A-6G. Sensor 22 includesthree magnetized regions 46 a, 46 b, 46 c which circumferentially extendaround the shaft. Sensor 22 includes two sensor housings 44 a and 44 b(i.e., top sensor housing 44 a and bottom sensor housing 44 b). Eachsensor housing 44 a, 44 b includes therein a pair of magnetic fluxsensing elements. Top sensor housing 44 a further includes therein athermistor. Sensor housings 44 a, 44 b are respectively placed in (topand bottom) windows 63 a, 63 b of the stator shaft of stator support 40such that sensor housings 44 are respectively adjacent to magnetizedregions 46 a, 46 b and magnetized regions 46 b, 46 c. As such, the pairsof sensing elements sense the torque induced magnetic flux respectivelyemanating from magnetized regions 46 a, 46 b and 46 b, 46 c when load isapplied to the shaft.

Electronics interface assembly 90 includes wiring segments 82 and 84(“84”), an application specific integrated circuit (ASIC) 94, and aconnector 96. Wiring 84 runs from sensor housings 44 a, 44 b (moreparticularly, from the fluxgate pairs and the thermistor) and connectsASIC 94 and connector 96 to the fluxgate pairs and the thermistor and toeach other. Connector 96 is connected to a power supply 98 for enablingpower supply 98 to supply power to ASIC 94 for its operation. Connector96 is also connected to a wiring harness of which PCM 100 is associatedin order to enable ASIC 94 to communicate with PCM 100.

In general, ASIC 94 provides drive signals to the fluxgate pairs andreceives corresponding output signals from the fluxgate pairs in ordermeasure the torque of the shaft. ASIC 94 also provides a drive signal tothe thermistor and receives a corresponding output signal from thethermistor in order to measure the temperature of the shaft. ASIC 94provides the torque measurements and the temperature measurement of theshaft to PCM 100.

The shaft is circumferentially magnetized within a band as indicated.The application of torque to the shaft results in opposite magneticpoles forming on the opposite edges of the band, with a toroidal fieldbeing generated above the surface of the shaft. The fluxgates areconfigured to detect the toroidal field. Each fluxgate includes a corewhich is relatively easily saturated by the combination of a drivereference signal (e.g., a square wave) and the magnetic field generatedby the magneto-elastic effect. In particular, ASIC 94 drives eachfluxgate with a square wave signal, compares the output to the referencesignal utilizing a Wheatstone bridge, and amplifies the measured voltagedifference from the bridge to obtain the torque output signal.

A thermistor is located near the shaft as indicated. The thermistor isused to compensate for the change in the magneto-elastic effect causedby varying temperature. This gives electronics interface assembly 90 theadditional tasks of driving the thermistor, reading the temperature(i.e., the temperature output signal), and adjusting the torque outputsignal according to the temperature.

As shown in FIG. 7, wiring 84 of electronics interface assembly 90includes five individual wires between the two sensor housings 44 andASIC 94. In particular, these five individual wires include: a firstwire 101 labeled “Pair 1 In”; a second wire 102 labeled “Common Out”; athird wire 103 labeled “Thermistor In”; a fourth wire 104 labeled“Thermistor Out”; and a fifth wire 105 labeled “Pair 2 In.” As furthershown in FIG. 7, two individual wires of electronics interface assembly90 are between sensor housing 44 themselves. In particular, these twoindividual wires include a sixth wire 106 and a seventh wire 107.

In operation, ASIC 94 provides a drive reference signal (i.e., a squarewave signal) over first wire 101 to top sensor housing 44 a and providesanother drive reference signal over fifth wire 105 to bottom sensorhousing 44 b. The drive reference signals drive the fluxgate pairs ofsensor housings 44 a, 44 b. The respective output signals from thefluxgate pairs are received by ASIC 94 over second wire 102. Inparticular, the output signal from the fluxgate pair of top sensorhousing 44 a travels over sixth wire 106 to bottom sensor housing 44 b,this output signal and the output signal from the fluxgate pair ofbottom sensor housing 44 a travel over seventh wire 107 to top sensorhousing 44 a, and the two output signals then travel from top sensorhousing 44 a to ASIC 94 over second wire 102.

ASIC 94 also provides a drive reference signal over third wire 103 totop sensor housing 44 a. This drive reference signal drives thethermistor. The output signal from the thermistor is received by ASIC 94over fourth wire 106.

As such, ASIC 94 includes the following inputs: power supply and ground.ASIC 94 further includes a reflash 1 input and a reflash 2 input.Reflash 1 and reflash 2 inputs are provided individually by ASIC tosensor housings 44 a, 44 b in order to reset or reconfigure the fluxgatepairs. ASIC 94 provides such reflash signals to sensor housings 44 a, 44b over first wire 101 and/or fifth wire 105 in lieu of the drivereference signals during the resetting or reconfiguration process. Theoutputs of ASIC 94 include the measured torque and measured temperatureof the shaft.

As described, electronics interface assembly 90 includes threemagnetized bands 46 a, 46 b, 46 c on the shaft, two fluxgate pairs and athermistor near the shaft, and the electronics. The magnetized bands arearranged in alternating polarity and the pair of fluxgates in each ofsensor housings 44 within respective sensor windows 63 of the statorshaft read only two of the three magnetized bands. The fluxgates and thethermistor are enclosed in capsules (i.e., the sensor housings 44) toprotect against contact with the transmission fluid. Sensor housings 44are sized to place the fluxgates at a fixed location within the sensorwindows 63. Sensor housings 44 are attached together by a lead framewhich minimizes the size of the wiring channels, while providingplacement of the wires during assembly and operation. The electronicsalso provide failure mode information, as well as temperature and torquesignals to the PCM. Pulse width modulated signals are chosen as a meansof communication to minimize the impact of noise on the signals.

Referring now to FIG. 8, with continual reference to FIG. 7, a blockdiagram of a transmission shaft with an electronics interface assembly110 for a magnetic torque sensor in accordance with another embodimentof the present invention is shown. The transmission shaft is the shaftof a transmission such as transmission 60 described with reference toFIGS. 6A-6G. Electronics interface assembly 110 is similar toelectronics interface assembly 90 and like elements are labeled with thesame reference numbers. One difference between the two assemblies is thelack of sixth and seventh wires 106 and 107 between sensor housings 44a, 44 b. As such, electronics interface assembly 110 lacks a “commonout” wire leading to ASIC 94 and instead includes two separate “out”wires leading to ASIC 94. Correspondingly, another difference is thatASIC 94 of electronics interface assembly 110 lacks the reflashcapabilities of electronics interface assembly 90.

As described, various features of transmission 60 applicable toelectronic interface assemblies 90 and 110 include the following. Aregion of a transmission shaft located inside of a torque converterstator support is magnetized. The torque converter stator supportincludes a housing of magnetic flux sensors (which may also be referredto as a bobbin, sensor housing, or PC board). The sensor housingincludes one or more magnetic flux sensing elements such as fluxgates.The sensor housing may include other sensors such as a thermistor.Electrical wiring attached to the sensor housing is routed out of thetransmission case through unique pathways designed into the statorsupport and its surrounding components. The stator support is uniquelydivided into multiple sections to enable the placement of the sensorhousing and the wiring.

As described, embodiments of the present invention are directed toautomatic transmissions with electronic interface assemblies formagnetic torque sensors configured to sense torque and/or speed of inputand/or output shafts in the transmissions. The exemplary transmission 60described in conjunction with electronic interface assemblies 90 and 110includes an input sensor for sensing torque of an input shaft. Ofcourse, such electronic interface assemblies may be for an output sensorconfigured to sense torque of an output shaft. Likewise, othertransmissions may be provided with various aspects of such electronicinterface assemblies.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the present invention.Rather, the words used in the specification are words of descriptionrather than limitation, and it is understood that various changes may bemade without departing from the spirit and scope of the presentinvention. Additionally, the features of various implementingembodiments may be combined to form further embodiments of the presentinvention.

What is claimed is:
 1. A transmission comprising: a shaft; sensorspositioned adjacent respective pairs of magnetized bands on the shaftfor detecting magnetic flux emanating from the bands in response totorque on the shaft; and an electronics interface assembly configured toprovide drive signals to the sensors and to receive from the sensors, inresponse to the drive signals, output signals indicative of the torqueon the shaft as detected by the sensors.
 2. The transmission of claim 1wherein: the electronics interface assembly includes a controller andwiring; and the controller is connected to the sensors by the wiring,provides the drive signals to the sensors, and receives from thesensors, in response to the drive signals, the output signals indicativeof the torque on the shaft as detected by the sensors.
 3. Thetransmission of claim 2 wherein: the drive signals are square wavesignals.
 4. The transmission of claim 2 wherein: the controller is anapplication specific integrated circuit.
 5. The transmission of claim 2wherein: the controller is connected to a power supply via the wiring.6. The transmission of claim 5 wherein: the electronics interfaceassembly further includes a connector; and the connector is connected toone of the controller and the power supply to connect the controller tothe power supply via the wiring.
 7. The transmission of claim 2 wherein:the wiring includes a plurality of wires; the controller is connected toa first one of the sensors via a first one of the wires to provide oneof the drive signals to the first one of the sensors; and the controlleris connected to a second one of the sensors via a second one of thewires to provide another one of the drive signals to the second one ofthe sensors.
 8. The transmission of claim 7 wherein: the controller isconnected to the first one of the sensors via a third one of the wiresto receive one of the output signals from the first one of the sensors;and the controller is connected to the second one of the sensors via afourth one of the wires to receive another one of the output signalsfrom the second one of the sensors.
 9. The transmission of claim 7wherein: the first one and the second one of the sensors are connectedtogether by a wiring sub-assembly such that the first one and the secondone of the sensors can communicate signals over the wiring sub-assembly;and the controller is connected to the first one of the sensors via athird one of the wires to receive the output signals from the first oneand the second one of the sensors.
 10. The transmission of claim 7further comprising: a thermistor positioned adjacent one of the sensorsfor detecting temperature of the shaft; and wherein the controller isfurther configured to provide a power signal to the thermistor and toreceive from the thermistor, in response to the power signal, atemperature signal indicative of the temperature of the shaft.
 11. Thetransmission of claim 10 wherein: the controller is connected to thethermistor via a third one of the wires to provide the power signal tothe thermistor; and the controller is connected to the thermistor via afourth one of the wires to receive the temperature signal from thethermistor.
 12. The transmission of claim 7 wherein: the controller isfurther configured to provide a reflash signal to the first one of thesensors via the first one of the wires; and the controller is furtherconfigured to provide a reflash signal to the second one of the sensorsvia the second one of the wires.
 13. The transmission of claim 1wherein: each sensor is positioned within a sensor housing adjacent to arespective pair of the magnetized bands.
 14. The transmission of claim 1wherein: each sensor includes a pair of fluxgates.
 15. The transmissionof claim 1 wherein: each sensor includes one or more fluxgates.